X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/fb467548a1501cae398e5bdab6794926da2690ef..ee9b1404a97247490a09fcf10af83a76a3d3d72d:/dstr.c

diff --git a/dstr.c b/dstr.c
index 6304351..e43e138 100644
--- a/dstr.c
+++ b/dstr.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: dstr.c,v 1.6 1999/05/21 08:38:33 mdw Exp $
+ * $Id: dstr.c,v 1.9 1999/07/06 19:16:06 mdw Exp $
  *
  * Handle dynamically growing strings
  *
@@ -30,6 +30,15 @@
 /*----- Revision history --------------------------------------------------*
  *
  * $Log: dstr.c,v $
+ * Revision 1.9  1999/07/06 19:16:06  mdw
+ * Simplify buffer-growing algorithm.  Just double it each time.
+ *
+ * Revision 1.8  1999/06/01 09:47:52  mdw
+ * Fix nasty bugs in `dstr_vputf'.
+ *
+ * Revision 1.7  1999/05/21 22:14:30  mdw
+ * Take advantage of the new dynamic string macros.
+ *
  * Revision 1.6  1999/05/21 08:38:33  mdw
  * Implement some more functions in terms of macros.
  *
@@ -66,8 +75,21 @@
 
 /*----- Tunable constants -------------------------------------------------*/
 
+/* --- Buffer expansion parameters --- *
+ *
+ * If the buffer is empty, it is set to @DSTR_INITSZ@ bytes in size.
+ * Otherwise, it's set to the next power of two that's large enough.  This is
+ * memory-hungry, but efficient.
+ */
+
 #define DSTR_INITSZ 256			/* Initial buffer size */
-#define DSTR_INCSZ 4096			/* Threshhold for doubling */
+
+/* --- Parameters for @dstr_putf@ --- *
+ *
+ * For each format specifier, at least @DSTR_PUTFSTEP@ bytes are ensured
+ * before writing the formatted result.
+ */
+
 #define DSTR_PUTFSTEP 64		/* Buffer size for @putf@ */
 
 /*----- Main code ---------------------------------------------------------*/
@@ -126,22 +148,14 @@ void dstr_ensure(dstr *d, size_t sz)
   if (rq <= d->sz)
     return;
 
-  /* --- Grow the buffer --- *
-   *
-   * For small buffers, just double the size.  For big buffers, make them
-   * a multiple of some suitably large chunk size.
-   */
+  /* --- Grow the buffer --- */
 
   nsz = d->sz;
 
-  do {
-    if (nsz == 0)
-      nsz = DSTR_INITSZ;
-    else if (d->sz < 0x1000)
-      nsz <<= 1;
-    else
-      nsz = (rq + 0x0fff) & ~0x0fff;
-  } while (rq > nsz);
+  if (nsz == 0 && rq < DSTR_INITSZ)
+    nsz = DSTR_INITSZ;
+  else
+    do nsz <<= 1; while (nsz < rq);
 
   if (d->buf)
     d->buf = xrealloc(d->buf, nsz);
@@ -205,11 +219,11 @@ int dstr_vputf(dstr *d, const char *p, va_list ap)
   const char *q = p;
   size_t n = d->len;
   size_t sz;
+  dstr dd = DSTR_INIT;
 
   while (*p) {
     unsigned f;
     int wd, prec;
-    dstr dd;
 
     enum {
       f_short = 1,
@@ -233,7 +247,6 @@ int dstr_vputf(dstr *d, const char *p, va_list ap)
 
     /* --- Sort out the various silly flags and things --- */
 
-    dstr_create(&dd);
     DPUTC(&dd, '%');
     f = 0;
     sz = DSTR_PUTFSTEP;
@@ -276,7 +289,7 @@ int dstr_vputf(dstr *d, const char *p, va_list ap)
 	  goto getnum;
 	default:
 	  if (isdigit((unsigned char)*p)) {
-	    f |= f_prec;
+	    f |= f_wd;
 	    ip = &wd;
 	    goto getnum;
 	  }
@@ -289,12 +302,12 @@ int dstr_vputf(dstr *d, const char *p, va_list ap)
 	    DENSURE(&dd, DSTR_PUTFSTEP);
 	    dd.len += sprintf(dd.buf + dd.len, "%i", *ip);
 	  } else {
-	    *ip = *p + '0';
+	    *ip = *p - '0';
 	    DPUTC(&dd, *p);
 	    p++;
 	    while (isdigit((unsigned char)*p)) {
 	      DPUTC(&dd, *p);
-	      *ip = 10 * *ip + *p++ + '0';
+	      *ip = 10 * *ip + *p++ - '0';
 	    }
 	  }
 	  break;
@@ -396,13 +409,14 @@ int dstr_vputf(dstr *d, const char *p, va_list ap)
     }
 
   formatted:
-    dstr_destroy(&dd);
+    DRESET(&dd);
     q = ++p;
   }
 
   DPUTM(d, q, p - q);
 finished:
   DPUTZ(d);
+  DDESTROY(&dd);
   return (d->len - n);
 }